This invention relates to "nets" for use in clearing swimming pools, fishing, and the like and more particularly, it relates to replacement "nets" for use in the aforementioned areas.
"Nets" of the type to which this invention relates generally comprise a net, a net-supporting ring or frame, and a sometimes segmented handle to which the frame may be permanently or detachably connected. In some cases, a tubular plastic cover is fitted over the frame to protect it and the net where it loops over the frame from abrasion, impact, etc., to maximize the life of a net.
Both normal and abnormal wear and tear produce holes in nets, thereby requiring their replacement before the end of the useful lives of the devices incorporating such nets. Additionally, the plastic protective covers (which may be designed to provide a projecting edge to facilitate scraping in the case of swimming pool skimmers) wear through so that they then no longer function as required.
If a net is torn or abraded, the usual remedy is to replace the entire net and frame structure (including at least a short length of handle). This can be quite expensive. For example, an average of three nets per commercial swimming pool skimmer need replacement each year. This means that owners of commercial swimming pool cleaning businesses must have a large inventory of replacement units on hand at all times. Thus, such persons have a considerable investment in replacement units.
In an attempt to overcome the foregoing problems relating to net breakage, a replacement net structure has been described in U.S. Pat. No. 2,783,573, issued Mar. 5, 1957 and entitled "Fish Net Having Detachable Ring." Briefly, the described structure comprises a rigid open tubular frame connected to a handle and defining a downwardly-facing continuous groove. A deformable, discontinuous ring supports a net and extends through the rigid frame so that the net extends downwardly through the frame groove. Means are provided to hold the ends of the deformable ring in proximity to each other after it has been threaded through the rigid tubular frame. Although the result is a replacement net which eliminates replacement of the rigid frame and attached handle section, threading of the deformable ring through the rigid frame can be time-consuming and the need to use attachment means to hold the ends of the deformable ring in position increases the number of components and the cost of manufacture. Cost is further increased by the need to thread the deformable rings through their respective associated nets.
Devices which include a protective, deformable rigid ring cover may inherently provide for net replacement. Such a device is described in U.S. Pat. No. 3,220,037, issued Nov. 30, 1965, and entitled "Swimming Pool Cleaning Implement." Described therein is an implement which includes a net-supporting, rigid ring, formed from channel stock, a handle attached to the latter, and a deformable cover of generally rectangular cross-section which defines a slot extending along its underside and which is capable of being snapped over the rigid ring after the free edge of a net has been folded over it to thereby retain the net against the ring. The disadvantage of this approach is that folding the free end of a net over the rigid ring and then holding it in that position while the deformable cover is snapped over it can be very difficult, particularly for a person without special equipment. Additionally, to prevent rotation of the cover about the rigid ring, the described prior art device is limited to implements in which the rigid ring is formed from flat stock.
Other, but unpatented, replacement devices are also presently available. One comprises a rigid frame of circular cross-section having a pair of laterally-extending ends connected together by a plate which is attachable to a handle. In order to hang a net on the frame, the plate must be disconnected therefrom to permit separation of the frame ends so that a net having a continuous loop along its upper edge can be threaded along the frame. After the frame ends have been reconnected at the plate, a deformable, tubular plastic cover defining a slot along one side is slipped over the frame to enclose the upper edge of the net therebetween. The plastic cover has a generally circular cross-section and a pair of outwardly-projecting flanges extending along the cover's length adjacent to the slot so that the cross-section of the cover generally has the shape of Greek letter omega. Replacement of a net on this device requires the use of tools and is time-consuming. Additionally, fitting the cover over the frame can be quite difficult because the cover tends to spiral around the frame. On the other hand, the cover has a tendency to rotate about the frame because it loosely fits the frame so that the protection which it should offer the net is reduced.
Another presently-marketed device utilizes a yoke-shaped frame connectable at the center of its closed end to a handle and having a pair of juxtaposed legs extending forwardly from the closed end. A relatively-rigid ring-shaped cover is formed to be removeably fitted to the frame. That cover has an L-shaped cross-section with one leg of the "L" forming an inner peripheral wall and with the other leg forming a floor (with the cover positioned horizontally). A shortened wall extends parallel to the adjacent floors from each of the side walls to define outwardly-opening grooves therebetween sized to snugly receive the forwardly-projecting legs of the frame. A pair of short arcuate walls extend upwardly from the floor of the cover at its rear corners to define upwardly-opening slots (when the cover is horizontally disposed) to snugly receive the rear corners of the frame. A net is formed integral with the cover so that it is removed with the cover. Replacement of the cover and net is relatively easy. However, because part of the cover is unsupported by the frame, stresses can be applied to the cover during use which can cause it to pop off the frame. On the other hand, it is recommended to use a tool such as a screwdriver to remove the cover from the frame.
A third unit comprises a frame made from channel stock having a continuous groove extending along an inner side thereof for receiving a continuous rib extending inwardly from a side wall of a tubular plastic cover which is generally U-shaped in cross-section and which is sized to be frictionally slipped over the frame after the open edge of a net had been looped over the latter. This cover is limited to use with frames having rectangular cross-sections. Additionally, it is difficult for a person to loop a net over the frame and to then snap the cover thereover.
In view of the present state of the art "net" devices, there is a continuing need for a replaceable net and frame cover which can be easily fitted to a frame by hand pressure, which will not be distorted or removed from the frame by use, and which can be readily removed by hand pressure to replace a net.